The present embodiments relate to ultrasound image simulation. Ultrasound images are easily acquired during an interventional or radiotherapy procedure. However, ultrasound images may lack the resolution or detail of computed tomography (CT) images. A CT volume may be acquired prior to the procedure and may be valuable for guidance during the procedure.
By registering the ultrasound images with the pre-operative CT volume, real-time and detailed information are both provided during the procedure. To register these different modalities, the CT volume may be used to simulate an ultrasound image. The pseudo-ultrasound simulations may better register with the actual ultrasound images. To simulate ultrasound from the CT volume, the acoustic properties (e.g., density of tissue) from the CT volume are used. The Houndsfield Unit (HU) from CT may be used as an estimate of density.
Magnetic resonance (MR) imaging may have different or greater variety of functional and/or anatomical information than CT imaging. However, MR imaging does not produce information as closely resembling density as provided by CT imaging. Physical sensors or feature recognition may be used for registration of ultrasound with MR, but sensors and feature recognition may make examination more expensive or difficult or be inaccurate.